First complete mitogenomes of three mayflies in the genus Afronurus (Ephemeroptera: Heptageniidae) and their implications for phylogenetic reconstruction

Heptageniidae is one of the most species-rich families within Ephemeroptera, whose evolution pattern of mitogenomes and internal relationships remain unclear. In this study, the complete mitochondrial genomes (mitogenomes) of Afronurus rubromaculata , A. yixingensis and A. obliquistrita were firstly sequenced and analyzed. Three mitogenomes share similar gene arrangement with an extra trnM gene compared with the ancestral order for insects. Comprehensive analysis of tRNA secondary structures showed that the extra trnM had a high level of nucleotide variation. The conservative intergenic spacer (IGS) region in the mitogenomes was found between the trnA and trnR genes with a size of 39 nucleotides and all formed a loop-stem structure. Furthermore, tandem repeats were identified in the control region of all three mitogenomes. The phylogenetic analyses using both Bayesian inference (BI) and maximum likelihood (ML) methods based on three datasets all supported that Heptageniidae was a monophyletic family. Our results supported the relationships (( A. rubromaculata + A. obliquistrita ) + A. yixingensis ) within Afronurus . The analysis will improve our understanding of the mitogenome features of heptageniid mayflies and lay the foundation for further phylogenetic study of Ephemeroptera.